Yanpeng Liu

Publications (3)3.97 Total impact

• Article: Biruloquinone, an Acetylcholinesterase Inhibitor Produced by Lichen-Forming Fungus Cladonia macilenta.

  Heng Luo, Changtian Li, Jin Cheol Kim, Yanpeng Liu, Jae Sung Jung, Young Jin Koh, Jae-Seoun Hur
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  ABSTRACT: At present, acetylcholinesterase (AChE) inhibitors are the first group of drugs to treat mild to moderate Alzheimer's disease (AD). Although beneficial in improving cognitive and behavioral symptoms, the effectiveness of AChE inhibitors has been questioned since they do not delay or prevent neurodegeneration in AD patients. Therefore, in the present study, in order to develop new and effective anti-AD agents from lichen products, both the AChE inhibitory and the neuroprotective effects were evaluated. The AChE inhibitory assay was performed based on Ellman's reaction, and the neuroprotective effect was evaluated by using the MTT method on injured PC12 cells. One AChE inhibitor (IC50 = 27.1 microg/ml) was isolated by means of bioactivity-guided isolation from the extract of lichen-forming fungus Cladonia macilenta, which showed the most potent AChE inhibitory activity in previous screening experiment. It was then identified as biruloquinone by MS, and 1H- and 13C-NMR analyses. The inhibitory kinetic assay suggested that biruloquinone is a mixed-II inhibitor on AChE. Meanwhile, biruloquinone improved the viability of the H2O2- and beta-amyloid-injured PC12 cells at 1 to 25 microg/ml. The protective effects are proposed to be related to the potent antioxidant activities of biruloquinone. These results imply that biruloquinone has the potential to be developed as a multifunctional anti- AD agent.
  Journal of Microbiology and Biotechnology 02/2013; 23(2):161-6. · 1.38 Impact Factor
• Article: Antioxidant activities of edible lichen Ramalina conduplicans and its free radical-scavenging constituents

  Heng Luo, Xinli Wei, Yoshikazu Yamamoto, Yanpeng Liu, Lisong Wang, Jae Sung Jung, Young Jin Koh, Jae-Seoun Hur
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  ABSTRACT: The aim of this study was to evaluate the antioxidant properties of an edible lichen Ramalina conduplicans. The extract exhibited potent anti-linoleic acid peroxidation activity, free radical-scavenging activity, and reducing power. The total phenolic contents were found to be high in the extract. Activity-guided bioautographic thin layer chromatography (TLC) and HPLC identified sekikaic acid and homosekikaic acid as the main free radical-scavenging compounds in R. conduplicans extract (IC50 [50% inhibition concentration]=0.082 and 0.276mg/ml, respectively). The results suggested that this edible lichen species have the potential to be utilized as food additives or as protective drugs. KeywordsBioautographic TLC-Homosekikaic acid-In vitro-Sekikaic acid-Total phenolic contents
  Mycoscience 04/2012; 51(5):391-395. · 1.21 Impact Factor
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  Article: The In vitro antioxidant properties of chinese highland lichens.

  Heng Luo, Yoshikazu Yamamoto, Yanpeng Liu, Jae Sung Jung, Hyung-Yeel Kahng, Young Jin Koh, Jae-Seoun Hur
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  ABSTRACT: Antioxidant properties of 46 lichen species collected from high-UV exposed alpine areas of southwestern China were evaluated for their therapeutic utilization. Anti-linoleic acid peroxidation activity, 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity, reducing power and the total phenolic contents were assessed in methanol extract of the lichens in vitro. Extracts of Peltigera praetextata and Sticta nylanderiana exhibited potent activity in all antioxidant tests. Especially, extracts of S. nylanderiana exhibited 1.37 times higher anti-linoleic acid peroxidation activity than ascorbic acid used as a positive control. It also showed the strongest free radical scavenging activity among all the tested species with an inhibition of 90.4% at the concentration of 330microgram/ml. Potent reducing power was also detected in the lichen extract compared with BHA. Generally, the antioxidant lichens contained large amount of phenolic contents. The activity-guided bioautographic TLC and HPLC analysis are used to find out the compounds responsible for the potent antioxidant activities of S. nylanderiana extract. The analysis demonstrated that lecanoric acid is one of the effective antioxidant compounds in S. nylanderiana. The results suggested that several highland lichens can be used as a novel bioresource for natural antioxidants.
  Journal of Microbiology and Biotechnology 11/2010; 20(11):1524-8. · 1.38 Impact Factor